Printed Circuit Board for Transmission Control

ABSTRACT

A printed circuit board for transmission control and for arrangement on an interface is disclosed. The printed circuit board includes an upper side of the printed circuit board and an underside of the printed circuit board. A plurality of spaced-apart conductor tracks arranged at a distance from the upper side of the printed circuit board. The conductor tracks are connected to each other in an electrically conductive manner by way of a first plated-through hole. The first plated-through hole is drilled out on the underside of the printed circuit board in such a way that it is arranged so as to be set back in relation to the underside of the printed circuit board. The printed circuit board is arranged on an interface, the underside of the printed circuit board facing the interface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of International ApplicationPCT/EP2019/062733, filed May 16, 2019, which claims priority to GermanApplication DE 10 2018 210 469.7, filed Jun. 27, 2018. The disclosuresof the above applications are incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates to a printed circuit board used for transmissioncontrol.

BACKGROUND

The use of printed circuit boards used for transmission control isknown. In the case of the known printed circuit boards, it is providedthat they have a plurality of conductor tracks that are spaced apartfrom one another. The conductor tracks are connected to one another inan electrically conductive manner by a plated-through hole. It isprovided that the plated-through hole is made to extend from the upperside of the circuit board to the underside of the circuit board. Due tothe manufacturing process, on the upper side and underside of thecircuit board the plated-through hole has a protrusion, which is usuallyalso referred to as a residual ring.

If such a printed circuit board were arranged on an interface in atransmission, the printed circuit board would be connected to theinterface in an electrically conductive manner due to the protrusion ofthe plated-through hole on the underside of the circuit board. This isto be avoided. It is therefore known that an insulating layer, which isalso known among other things as a thermal interface, is arrangedbetween the printed circuit board and the interface. Electricalinsulation between the printed circuit board and the interface can beprovided by means of the thermal interface between the underside of thecircuit board and the interface.

Since the printed circuit board is installed in a transmission, andconsequently can come into contact in the transmission with variousaggressive media, such as for example transmission oil, there is therisk that the thermal interface may break down due to the aggressivemedia. This has the effect that the adhesive action of the printedcircuit board in relation to the interface may be reduced. In addition,the dissolved or detached material of the thermal interface may bedistributed in the transmission.

SUMMARY

The disclosure relates to a transmission control apparatus for a motorvehicle that includes a printed circuit board for transmission controland an interface supporting the printed circuit board. The disclosurealso relates to the use of the printed circuit board for transmissioncontrol and the interface. In this case, it is provided that aplated-through hole made to extend through the printed circuit board forthe electrical connection of the conductor tracks arranged within theprinted circuit board is formed as set back in relation to an undersideof the circuit board. In this way, when the printed circuit board isarranged on the interface with the underside of the circuit board facingthe interface, electrical insulation of the printed circuit board inrelation to the interface can be provided in a simple manner due to theset-back formation of the plated-through hole.

Therefore, the disclosure specifies the use of a printed circuit boardfor transmission control and for arrangement on an interface, wherethermal and/or electrical insulation that has increased resistance tomedia is provided between the printed circuit board and the interface.

Implementations of the disclosure may include one or more of thefollowing optional features. In some implementations, the printedcircuit board has between an upper side of the circuit board and anunderside of the circuit board arranged at a distance from the upperside of the circuit board a plurality of spaced-apart conductor tracks,which are connected to each other in an electrically conductive mannerby way of a first plated-through hole, where the first plated-throughhole is drilled out on the underside of the circuit board in such a waythat it is arranged so as to be set back in relation to the underside ofthe circuit board, and the printed circuit board may be arranged on aninterface, the underside of the circuit board facing the interface.

In other words, one aspect of the disclosure provides a printed circuitboard for transmission control is arranged on an interface. The printedcircuit board may be integrated in a transmission, the transmission maybe designed for a motor vehicle. In some examples, the printed circuitboard is arranged within the transmission as a wiring level, in order tocombine both the power areas and the logic areas on one circuit carrier.The interface is arranged in the transmission and is used, among otherthings, for fastening the printed circuit board.

The printed circuit board has an upper side of the circuit board and anunderside of the circuit board, which is arranged at a distance from theupper side of the circuit board. The upper side of the circuit board andthe underside of the circuit board may be arranged essentially parallelto one another. A plurality of conductor tracks that are spaced apartfrom one another are formed and/or arranged between the upper side ofthe circuit board and the underside of the circuit board. The conductortracks are connected to one another in an electrically conductive mannerby way of a first plated-through hole through the printed circuit board.The first plated-through hole is consequently made to extend from theupper side of the circuit board to the underside of the circuit board.The first plated-through hole is drilled out on the underside of thecircuit board. The plated-through hole is therefore formed as set backin relation to the underside of the circuit board.

The printed circuit board is designed to be connected to an interface.It is in this case provided that the underside of the circuit boardfaces the interface. Due to the drilling out of the plated-through hole,as a result of which the plated-through hole is no longer flush with theunderside of the circuit board, but rather is formed as set back, theprinted circuit board may be arranged on the interface in anelectrically insulating manner. In this way, the use of a printedcircuit board for transmission control and for arrangement on aninterface is provided, making it possible to dispense with the thermalinterface or the insulation material between the printed circuit boardand the interface by the first plated-through hole being drilled out onthe underside of the circuit board. Since no insulation material is thenrequired, the material costs for using the printed circuit board in atransmission control device for arrangement on an interface can bereduced. In addition, the risk of the insulation material dissolving dueto the aggressive media arranged in the transmission can be avoided.

In some implementations, a second plated-through hole is made to extendto the underside of the circuit board and/or has a protrusion inrelation to the underside of the circuit board, where the secondplated-through hole is connected in an electrically conductive manner toa ground layer arranged within the printed circuit board. It isaccordingly provided that the printed circuit board has in addition tothe first plated-through hole a second plated-through hole, which isformed from the upper side of the circuit board to the underside of thecircuit board. It is then provided that this second plated-through holeon the underside of the circuit board is not drilled out like the firstplated-through hole. Consequently, the second plated-through hole iseither formed flush with the underside of the circuit board and/or has aprotrusion in relation to the underside of the circuit board. The secondplated-through hole is only connected in an electrically conductivemanner to the ground layer arranged within the printed circuit board. Inthis way, in the event of a voltage-induced flashover, a discharge canbe diverted directly into the ground layer. The voltage-inducedflashover is therefore not harmful to the other circuit components ofthe printed circuit board.

In this context, in some examples, the second plated-through hole has asolder resist layer between the underside of the circuit board and/orthe protrusion in relation to the underside of the circuit board and theinterface. The solder resist layer is consequently arranged between thesecond plated-through hole and the interface. The solder resist layerdoes not have insulation resistance. This means that, as a furtherconsequence of a voltage-induced flashover, a discharge may be diverteddirectly into the ground layer of the printed circuit board andtherefore the risk of damage to the other circuit components of theprinted circuit board can be reduced.

In some implementations, it is provided that the first plated-throughhole and/or the second plated-through hole are each formed as a sleeve.This has the advantage that the sleeve may be inserted and fixed in athrough-hole which extends from the upper side of the circuit board tothe underside of the circuit board. An electrically conductiveconnection between the conductor tracks and the sleeve or between theground layer and the sleeve can therefore be established in a simplemanner.

In principle, the conductor tracks, the first plated-through hole and/orthe second plated-through hole may be formed from an electricallyconductive material. In some examples, the conductor tracks and/or thefirst plated-through hole and/or the second plated-through hole areformed from copper or at least comprise copper. By contrast with theother electrically conductive materials, copper has a relatively goodand high electrical conductivity and therefore causes low electricallosses. Consequently, the electrical conductivity of the printed circuitboard may be increased.

In some implementations, the sleeve is potted with a resin. The sleeveaccordingly has a cavity which is enclosed by the sleeve wall lyingagainst the printed circuit board. This cavity is potted with a resin.By filling the cavity of the sleeve, the durability of the sleeve, andtherefore the service life of the sleeve, may be increased. In addition,if the printed circuit board is later overmolded or encapsulated, it ispossible to avoid plastics material penetrating into the cavity of thesleeve and not completely filling it, but instead voids forming withinthe cavity of the sleeve. This allows the surface quality to beincreased when encapsulating the printed circuit board, which canincrease the impermeability of the encapsulation.

In some implementations, it is provided that the printed circuit boardis arranged on the interface in a form-fitting, material-bonding and/orforce-fitting manner. It is particularly advantageously provided thatthere is only a form-fitting and/or a force-fitting connection betweenthe printed circuit board and the interface. This has the advantagethat, as is the case with a material-bonding connection, it is possibleto dispense with adhesives. A material-bonding connection may have thedisadvantage that the adhesive could dissolve due to the aggressivemedia prevailing in the transmission. A force-fitting connection may bea screw connection. In this way, the printed circuit board can befastened and/or arranged on the interface in a simple manner. Similarly,a clip connection may also be provided for connecting the printedcircuit board and the interface.

In principle, the interface may be formed in such a way that it isarranged and/or designed to receive the printed circuit board. Anadvantageous development of the disclosure is that the interface is ahydraulic block of a transmission.

The details of one or more implementations of the disclosure are setforth in the accompanying drawings and the description below. Otheraspects, features, and advantages will be apparent from the descriptionand drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 shows a section through a printed circuit board which is arrangedon an interface, the printed circuit board having first plated-throughholes,

FIG. 2 shows a section through a printed circuit board which is arrangedon an interface, the printed circuit board having a first plated-throughhole and a second plated-through hole.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

In FIG. 1, a printed circuit board 10 for transmission control and forarrangement on an interface 12 is shown. The printed circuit board 10has an upper side 14 of the circuit board and an underside 16 of thecircuit board, which is arranged at a distance from the upper side 14 ofthe circuit board. The upper side 14 of the circuit board and theunderside 16 of the circuit board are arranged and/or formed essentiallyparallel to one another. A plurality of conductor tracks 18 arrangedspaced apart from one another are arranged between the upper side 14 ofthe circuit board and the underside 16 of the circuit board 10. Theconductor tracks 18 are connected to one another in an electricallyconductive manner by way of a first plated-through hole 20, which ismade to extend through the printed circuit board 10. The firstplated-through hole 20 is drilled out 22 on the underside 16 of thecircuit board in such a way that it is formed as set back in relation tothe underside 16 of the circuit board 10. The drilling out of theplated-through hole 20 on the underside 16 of the circuit board 10 isalso described as “back drilling”. By drilling out the firstplated-through hole, manufacturing-related remains of the firstplated-through hole near the underside of the circuit board are removed.Consequently, when the printed circuit board 10 is arranged on theinterface 12, electrical contacting of the printed circuit board 10 inrelation to the interface 12 can be avoided in the area of the firstplated-through hole 20.

By contrast with the known prior art, therefore no additional insulationmaterial is required for the electrically conductive insulation of theprinted circuit board 10 in relation to the interface 12. Consequently,on the one hand, insulation material between the printed circuit board10 and the interface 12 can be saved, as a result of which manufacturingcosts can be reduced. In addition, the risk of the insulation materialdissolving due to the aggressive media arranged in the transmission,such as for example transmission oil, which could contaminate thetransmission oil, can be avoided.

In some examples, the first plated-through hole 20 and the conductortracks 18 are formed from copper. Copper has a high conductivity.Consequently, electrical losses can be reduced.

The first plated-through hole 20 is formed as a sleeve 24. The sleeve 24has a sleeve cavity 26, which is enclosed at least in sections by thesleeve wall 28 adjoining the printed circuit board 10. The sleeve cavity26 is potted with a resin 30. By potting the sleeve cavity 26, it ispossible to avoid aggressive medium getting into this sleeve 24. In thisway, the durability of the sleeve 24 can be increased. In addition, thepotting of the sleeve cavity 26 has the advantage that, if the printedcircuit board 10 is later encapsulated or overmolded, the overmoldingmaterial does not have to laboriously find its way into the cavity ofthe sleeve 24. In this way, the quality of the encapsulating orovermolding process can be increased.

FIG. 2 shows the printed circuit board 10 known from FIG. 1 forarrangement on the interface 12, where, as a difference from FIG. 1, inFIG. 2 the printed circuit board 10 then has in addition to a firstplated-through hole 20 a second plated-through hole 32. The firstplated-through hole 20 shown in FIG. 2 is identical to the firstplated-through hole 20 shown in FIG. 1. The second plated-through hole32 is made to extend from the upper side 14 of the circuit board to theunderside 16 of the circuit board 10. The second plated-through hole 32is formed as a sleeve 24. The sleeve 24 has a protrusion 34 respectivelyon the upper side 14 of the circuit board and the underside 16 of thecircuit board. This protrusion 34 is usually a ring due to themanufacturing process that arises when the sleeve 24 is arranged andfixed in the printed circuit board 10. The second plated-through hole 32is arranged in the printed circuit board 10 in such a way that it isonly connected in an electrically conductive manner to a ground layer 36arranged in the printed circuit board 10.

It can also be seen that a solder resist layer 38 is arranged on theprotrusion 34, which protrudes beyond the underside 16 of the circuitboard 10, and is therefore arranged between the sleeve 24 and theinterface 12. The solder resist layer 38 does not have insulationresistance. Consequently, the second plated-through hole 32 is connectedin an electrically conductive manner to the interface 12, while thefirst plated-through hole 20 is arranged in an electrically conductivelyinsulated manner in relation to the interface 12 as a result of thedrilling out 22 in the first plated-through hole 20. Due to the factthat the second plated-through hole 32 is connected to the interface 12in an electrically conductive manner, in the event of a voltage-inducedflashover the discharge can be introduced directly into the ground layer36. In this way, voltage-induced damage to the further circuitcomponents of the printed circuit board 10 can be reduced and/oravoided.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure. Accordingly, otherimplementations are within the scope of the following claims.

What is claimed is:
 1. A printed circuit board for transmission controland for arrangement on an interface, the printed circuit boardcomprising: an upper side; an underside arranged at a distance from theupper side; and a plurality of spaced-apart conductor tracks positionedbetween the upper side and the underside, the plurality of spaced-apartconductor tracks are connected to each other in an electricallyconductive manner by way of a first plated-through hole, wherein thefirst plated-through hole is drilled out on the underside of the printedcircuit board in such a way that it is arranged so as to be set back inrelation to the underside of the printed circuit board, and wherein theprinted circuit board is arranged on an interface, the underside of theprinted circuit board facing the interface.
 2. The printed circuit boardas claimed in claim 1, wherein a second plated-through hole is made toextend to the underside of the printed circuit board and/or has aprotrusion in relation to the underside of the printed circuit board,wherein the second plated-through hole is connected in an electricallyconductive manner to a ground layer arranged within the printed circuitboard.
 3. The printed circuit board as claimed in claim 2, wherein thesecond plated-through hole has a solder resist layer between theunderside of the printed circuit board and/or the protrusion in relationto the underside of the printed circuit board and the interface.
 4. Theprinted circuit board as claimed in claim 2, wherein the firstplated-through hole and/or the second plated-through hole are eachformed as a sleeve.
 5. The printed circuit board as claimed in claim 4,wherein the sleeve is potted with a resin.
 6. The printed circuit boardas claimed in claim 1, wherein the conductor tracks and/or the firstplated-through hole and/or the second plated-through hole are formedfrom copper or at least comprise copper.
 7. The printed circuit board asclaimed in claim 1, wherein the printed circuit board can be arranged onthe interface in a form-fitting, material-bonding and/or force-fittingmanner.
 8. The printed circuit board as claimed in claim 1, wherein theinterface is a hydraulic block of a transmission.
 9. A transmissioncontrol apparatus for a motor vehicle, the transmission controlapparatus comprising: a printed circuit board including: an upper side;an underside arranged at a distance from the upper side; a firstplated-through hole drilled out on the underside of the printed circuitboard in such a way that it is arranged so as to be set back in relationto the underside of the printed circuit board; a plurality ofspaced-apart conductor tracks connected to each other in an electricallyconductive manner by way of the first plated-through hole; an interfacesupporting the printed circuit board, the underside of the printedcircuit board facing the interface.
 10. The transmission controlapparatus as claimed in claim 9, wherein the printed circuit boardfurther comprises: a second plated-through hole extending to theunderside of the printed circuit board and/or has a protrusion inrelation to the underside of the printed circuit board, a ground layerwherein the second plated-through hole is connected in an electricallyconductive manner to the ground layer.
 11. The transmission controlapparatus as claimed in claim 10, wherein the second plated-through holehas a solder resist layer between the underside of the printed circuitboard and/or the protrusion in relation to the underside of the printedcircuit board and the interface.
 12. The transmission control apparatusas claimed in claim 10, wherein the first plated-through hole and/or thesecond plated-through hole are each formed as a sleeve.
 13. Thetransmission control apparatus as claimed in claim 12, wherein thesleeve is potted with a resin.
 14. The transmission control apparatus asclaimed in claim 9, wherein the conductor tracks and/or the firstplated-through hole and/or the second plated-through hole are formedfrom copper or at least comprise copper.
 15. The transmission controlapparatus as claimed in claim 9, wherein the printed circuit board isarranged on the interface in a form-fitting, material-bonding and/orforce-fitting manner.
 16. The transmission control apparatus as claimedin claim 9, wherein the interface is a hydraulic block of atransmission.